Makita 233916-6 — Conical compression spring (21–29)
Description:
Genuine Makita conical compression spring used in the chuck/bit‑holding assembly of Makita rotary hammers. It provides axial tension in the chuck/locking mechanism so the bit locks and releases reliably; replace this spring if the chuck becomes loose, the bit won’t lock, or the mechanism feels weak. The part is specified as "Conical Comp. Spring 21‑29" in Makita parts diagrams.
Key details (metric):
- Type: conical (tapered) compression spring, designed to sit under the chuck cover.
- Nominal diameters: approximately 21 mm (small end) to 29 mm (large end).
- Typical wire / sizing listing: shown as roughly M1.4 × 21.3 × 28 mm on parts listings (wire diameter ≈ 1.4 mm, nominal coil diameter ≈ 21.3 mm at the small end, free length ≈ 28 mm).
Fits (examples):
Common Makita rotary‑hammer models that use this conical spring include HR2450F, HR2455, HR2432, HR2445, HR2470/2470F, HR2811F, BHR202/BHR202Z, BHR240Z, BHR241/BHR261 series and several HR26/HR26xx and DHR28x models. Referenced Makita parts breakdowns and lists this item as part of the chuck assembly for these model .
Notes for repair:
This is the specific spring that sits beneath the chuck cover and works with the guide washer, steel ball(s) and retaining rings in the tool’s bit‑locking cluster; replacing the spring restores proper chuck tension and bit retention. Check the exploded parts diagram for your model to confirm position and orientation before reassembly.
(Part number: 233916-6 — Conical Comp. Spring 21‑29, genuine Makita.)
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